Blurry Store Thumbnails on WooCommerce

I have tried changing themes, and editing the product images in Customizer but there is no change to the images (except the level of blurriness).
I have watched the woo commerce videos, but the support is no longer applicable as you cannot change the px size, just the ratio in the Woocommerce setting of the customizer.
Surely there must be something else I can do?

The images on the product page are fine, so it is not the image quality, but the way that the page resizes the image.

I have the Thumbnail Resizer plug in, which has not helped.

The page I need help with: [log in to see the link]